There are many types of systems that process, transport, or utilize a pressurized fluid. To ensure the safety of these types of systems, each such system typically includes a safety device designed to prevent (or at least provide an alarm indication during) the over-pressurization of the system. In an emergency situation, where the fluid in the system reaches an unsafe level, the pressure of the fluid acts on the safety device to create an opening to release fluid from the system. Outside of creating an opening, the safety device may simply provide an alert warning, indicating that a dangerous over-pressure situation is occurring. In devices that actually rupture, or otherwise open to environment, venting fluid to the environment or a safety reservoir through the opening reduces the pressure in the system and prevents another portion of the system from failing due to the high pressure of the fluid.
Examples of commonly used safety devices include rupture disks and explosion panels. These safety devices can be attached to a pressurized system to expose a certain portion of the device to the pressurized fluid in the system. Often, a portion of the device exposed to the fluid is configured to rupture or tear when the fluid reaches a predetermined pressure. The tearing or rupture of the disk or panel creates an opening through which the pressurized fluid flows to reduce the pressure in the system. This type of safety device is, therefore, self-destructing and must be replaced after each use. Typically, to replace one of these safety devices, some disassembly of the system is needed so that the disk or panel can be properly engaged with the system.
In addition, where the safety device is designed to rupture or automatically open (i.e., a self-destructing safety device), production and formation often requires precise scoring or otherwise weakening the material of the device in order to ensure opening at a particular location and pressure. For example, rupture disk formation often includes scoring, cutting, etching, or thinning material of the device to outline a predetermined “burst pattern.” This precise machining results in added manufacturing time and machinery, thereby increasing manufacturing costs.
In the field of “reverse buckling” rupture disk pressure relief devices, a concave/convex shaped structure has been used as a means of providing a reliable and reproducible pressure responsive device. Known “reverse buckling” devices are designed such that when the convex side of the structure is exposed to a predetermined overpressure force, the structure “buckles” and inverts causing the convex side to collapse into a concave shape. Moreover, at the predetermined overpressure force, the rupture disk is typically designed not only to invert, but also to open by means of a cutting device located downstream of the disk, or by virtue of a line of weakness produced by scoring, etching, or other means during the manufacturing process.
Within the broad category of concave/convex shaped structures used for reliable reverse buckling pressure response, there exist many shape subsets, such as, for example, a centered spherical dome, an offset spherical dome, a pyramid shape, and a truncated pyramid shape. The spherical dome shape, frequently used in known reverse buckling devices, suffers from a number of drawbacks. For example, a generally spherically shaped domed structure often only partially collapses during an over-pressure condition. In addition, a spherically shaped, partially domed structure may reverse in an irregular, or uneven, non-symmetrical manner, thereby leading to inconsistent results, particularly for smaller nominal sizes such as below 1″/25 mm diameter. Moreover, during shipping and packaging, the spherical shape is susceptible and often exposed to damage, or mishandling during shipping and packaging that adversely effects the desired response pressure (often leading to rupture or opening at a lower pressure than the set pressure). Finally, the scoring and etching required to form a reproducible burst pattern adds to the overall cost and profit associated with manufacturing.
There is a need for a pressure response structure that overcomes one or more of the deficiencies above and/or other deficiencies in the art.